Feeding mechanism for sewing machines



y 7, 1940. I F. A. KUCE RA Q v 2.199.666

FEEDING MECHANISM FOR SEWING swarms Filed Feb. 19, 19s,: s Sheets-Sheet 1' INVENTOR." Frank :7. imam BY 6% g I I oklvgys.

ITNESSES:

May 7, 1940. F. A. KUCERA FEEDING MECHANISM FOR sswmq mcnmzs 3 .SheetsSheet 2 Filed Feb. 19, 193'! INVENTOR: Frank flifucanl,

ATTORNEYS y -9 F.. A. KUCERA 2.199.666

FEEDING MECHANISM FOR SEWING MACHINES Fi led Feb. 19, 1931 :5 Sheets-Sheet 3 E a m a 6v 7 O mm o g I PM INVENTOR: Fran]: fi Huwra, BY romwsys.

Patented May'l,

UNITED STATES PATENT OFFICE I I FEEDING FOR SEWING I Frank A. Kucerachicago, Ill., assign'orto Union Special Machine Company, Chicago, Ill., a corporation of Illinois Application February '19, 1937, Serial No. 126,585"

19 Claims.

This invention relates to feeding mechanism for sewingm-achines, particularly for sewing machines of the type wherein the work support is tubular, as, for example, in what are known as feed-off-the-arm sewing machines.

- Due to inaccuracies in the machining of the feed bars or of the directly associated parts of the actuating mechanism, the feed dogs often fail to register properly with the openings provided for them in the throat plates or are out-of level transversely of the direction of feed. Under such conditions, the feed dogs will not progress the fabric uniformly with consequent pro.-

. duction of crooked seams. Moreover, in feedofI-the-arm machines, the feed dogs are usually in the form of cantilevers reaching forwardly beyond the ends of the feed bars, and are thus not directly supported from beneath for capacity to react upon the presser feet with an equal degree of resistivity throughout their fabric contact areas.

NW invention has for one of its aims to overcome the above drawbacks, which objection I realize in practice as hereinafter more fully disclosed, through provision of a feed bar whereof the forward end is of open yoke-like construction and overreaches the complemental ,stitch form ing instrumentalities that cooperate with the needle or needles of the sewing machinebeneath the throat plate; and through provision of a feed dog. which overlies the open forward end of the feed bar and which is supported with capacity for separate vertical adjustment at its opposite ends, as well as with capacity for angularadjustment transversely of the direction of feeding. e V Another aim of my invention is to insure against deflectionand bending of the needle or needles duringthe period of their coaction with the complemental stitch forming instrumentalities, which objective I also attain in practice. as hereinafter more, fully. disclosed, throughi provision of a ,.guard, whic h, like the feed dog, is supported with .capaci-ty for adjustment on the feed bar. fl.

. Other,-objec ts: and attendant, advantages will :appearfrom the following detailed description of the attachedxfdrawings, whereof Fig. I is a fragmentary view partly inside elevation and partly in longitudinal section,- ofa. feed off-the arm sewing" machine embodying my invention,

Fig. 11 is a long-itudinal sectional view'of the tubular work supportingarmof the machine in which t e feed an in loopermechanisms are m. mascara air siifipoitihgarm in plan with its top and endcovers removed to expose the feed mechanism.

Fig. IV shows the feed bar and the feed dog supported thereby, in end elevation.

Fig. V is a detail sectional view, taken as indi- .5 cated by the arrows VV in Fig. II.

Figs. VI, VII and VIII are cross sectionstaken as indicated respectively by the arrows VI-VI,

. VII-VII and VIII-VIII in F1g'.'II.

Fig. IX is a fragmentary plan sectional view, taken as indicated by the arrows IX-IX in Fig.

Fig. X is a detail sectional view, taken as indicated by the arrows X-X in Fig. IX. I

Figs. XI and XII are perspective views of the 1 feed dog and the needle guard respectively. Fig. XIII is a perspective view of a bracket piece by which the needle guard is .adjustably supported on the feed bar.

Fig XIV is a fragmentary tion of a modified form of feed bar and feed dog and Fig. XV shows the front end elevation of the modified feed bar and feed dog. The sewing machine chosen for convenience of illustrating the present improvements is of the feed-oif-the-arm type, generally similar in construction to the sewing machine featured in U. S. Patent No. 1,741,095, granted to Norman V. Christensen and Harold J. Le Vesconte on March 24, 1929. As shown, the machine has a frame with a horizontal upper member I in which a rotary drive shaft 2 is journaled, and with a tubular work supporting arm 3 which is secured, by means of screws 4 (Fig. I) to a pendant hollow projection 5 at one end of said upper member. The work supporting arm 3 extends hori zen-tally forward from the region of its connection to the member Land to the top of its free end is secured a throat plate 6 by means of screws I, see Fig. VI. The end section 8 and the cover section 9 of the'arm 3'are removable so that access' may be had to the parts within. Centrally of the work-supporting arm 3 is a longitudinal rock shaft II, which, near its ends is journaled in'bearin gs l2-and l3. Secured to thefront end of the rock shaft H is a carrier H for a plurality of'concentrically cu vedloopers l5-(in this instance, three) that cooperate beneath the throat plate 6 with as many needles l8 upon penetration of the latterdown through the fabric (not' shown) in a well known manner- The needles l6 are,

or course, actuated -in timed relation with the view in side eleva- 20 I 2 within the upper member I of the machine frame. The rock shaft II is oscillated as a consequence of the coordination of a ball crank (Figs. II and III) at its rear end with the strap be seen that the rocker I9 is mounted for oscillation about a transverse shaft whereof the ends are fixed by set screws 26 in bosses 21 at opposite sides of the work supporting arm 3 of the machine frame. As shown in Fig. II, the rocker arm 23 has a longitudinal slot 28 along which the ball pivot 22 can be shifted to adjust the axial throw of the shaft The rocker I9 is actuated from another eccentric 29 on the drive shaft 2, the associated strap rod 30 having a ball pivot connection at 3| with a horizontal arm 32 of said rocker.

The feed bar of the machine designated by a numeral 33 lies horizontally over the shaft within the hollow of the work supporting arm 3, and is supported at an intermediate point immediately inward of the bearing l2, by a pair of links 34. At their lower ends these links 34 are .pivotally connected to the front end of a lever 35 which is fulcrumed on a shaft 36 extending transversely of the work supporting arm 3 with its ends fixed in bosses 31 at opposite sides of said arm (see Figs. II and III). At its rear end, the lever 35 has a ball connection 33 with the strap rod 40 of a third eccentric 4| on the drive shaft '2. By the means just described, rise and fall movements are imparted to the feed bar 33, which also receives horizontal to and fro or feed movements by virtue of the connection of its rear end to a rocker 42'mounted for oscillation about another transverse shaft 43 whereof the ends are suitably journaled in bosses 44 at the sides of'the work supporting arm3, see Fig. VIII. The rocker 42 depends for its actuation upon the rocker l9 to an upward arm 45 of which it is connected by a pitman 46. As shown, the rocker arm 45 has an arcuate slot 41 concentric with the front pivot 48 of the pitman 46 along which slot the rear pivot 49 of said pitman can be shifted to adjust the feed movement of the feed bar and in turn the length of the stitch produced by the machine. In accordance with my invention, the forward end 50 0f the feed bar 33 is of a yoke-like construction and overreaches the loopers l5, said end being of angular cross section as will be observed from Fig. VII and having an opening 5| in its top and an opening 52 in its side for clearance of the loopers. The yoke-like portion 56 of the feed bar 33 is moreover formed centrally of its front end with a pendant projection 53.

Extending rearwardly over top of the yoke-like portion 50 at the free end of the feed bar 33 is a bridging feed dog 54 which is likewise of open construction (see Fig. XI) and which has toothed ridges projecting upward through a correspondingly shaped slot 55 in the throat plate 6. At its front end, the feed dog 54 has a pendant tongue 56 which engages a vertical groove 51 in the front face of the pendant end projection 56 of the feed bar 33. As shown in Figs. IV and X, the tongue 56 has a. longitudinal clearance slot 58 for the end of the feed dog 54 rests on a screw stud 6| which is adjustable in the top of the feed bar 33. The feed dog 54 is thus firmly and eifectively'supr Ported from be eath and able to resist the pi'essure of the presser foot (not illustrated) of they machine uniformly throughout its contact area without yielding to fiexure.

In order to guide and brace the needles l6 at the time that they cooperate directly with the loopers l5 beneath the throat plate 6 incident to stitch fomiation, I have provided a guard 62 which is separately illustrated in perspective in.

Fig. XII. As shown, this guard 62 has a plurality of bevel sided fingers 63 for engagement by the needles l6 respectively, and a horizontal shank 64 adapted to fit a groove or recess 65 in the horizontal top extremity 66 of an angular supporting bracket piece 61 which is separately illustrated in perspective in Fig. XIII. A cap screw 68 (Figs. IX and X) with its shank passing through a longitudinal slot 69 in the shank of the guard 82 and engaging a tapped hole 10 in the top of the bracket piece 61, serves to secure said guard to the bracket piece at a level immediately below the ends of the loopers 15 (Fig. VII). The pendant portion ll of the bracket piece 61 in turn fits a vertical slot at the back of the pendant projection 53 on the feed bar 33, whereto it is secured by a cap screw 13, the shank of which passes through a vertical slot 14 in said projection and engages atapped hole 15 in said bracket piece, see Figs. II, IV, V, IX and X. This arrangement permits both vertical and horizontal adjustment of the guard 62 in respect to the feed bar 33 so that perfect operative coordination between the needles I6 and the loopers l5 may be secured. The guard 61,, it will be noted from Figs. IX and X, is readily accessible for adjustment through the top and side openings 5| and 52 of the yokelike portion 50 of the feed bar 33.

In the modification featured in Figs. XIV and XV, the slot 51a in the front of the pendant projection 53a of the feed bar 33a is considerably wider than the tongue 56a of the feed dog 54a so that the latter canbe adjusted angularly about the cap screw 59a as well as vertically. Set screws I8 bearing against the opposite side edges of the tongue 56a below the cap screw 59a are relied upon to prevent displacement of the feed dog 54a in angularly adjusted positions. By virtue of the construction just described, the feed dog 54a can obviously be properly leveled transversely of the direction of feeding and centralized within the opening '55 of the throat plate 6 in compensating for inaccuracies in the machining of the feed bar 33, the feed liftlever 35,-etc.

Having thus described my invention, I claim:

1. Feeding mechanism for sewing machines comprising a feed bar; means for impartingto and fro and up and down movements to the bar;

an overlying feed dog with a pendant tongue at 'into the end of the feed relative to said bar;

ment to the front end of the feed bar; and means vertically adjustable in the top ofthe feed bar for supporting theother end of the feed dog. 3. Feeding mechanism for sewing machines bar; means for imparting to comprising a feed and fro and up and down movements to the bar; an overlying feed dog with a longitudinally slotted pendant tongue at one end; a cap screw with its shank passing through the slot of the tongue and engaging into the end of the feed bar; and a screw stud adjustably engaged in the top of the bar for supporting the other of the feed dog.

4. Feeding mechanism for sewing machines comprising a feed bar; means for imparting to and fro and up and down movements to the-bar; a feed dog with a pendant longitudinally slotted tongue; a cap screw with ,its shank passing through the slot of the tongue and engaging into the end of the feed bar, so that said dog can be adjusted vertically; and means whereby the tongue can be moved about the screw as an axis to angularly adjust the dog laterally of the direction of feeding.

5. Feeding mechanism for sewing machines coinprising a feed bar; means and fro and up and down movements to said bar; a feed dog with a pendant tongue pivotally connected to the end of the feed bar to permit angular adjustment of the feed dog laterally of said bar; and set screws engaged in the bar and adapted to bear against opposite sides of the tongue beyond the pivotal connection to hold the dog against displacement in angularly adjusted positions.

6. Feeding mechanism for sewing machines comprising a feed bar; means for imparting to and fro and up and down movements to the bar;

a feed dog with a pendant longitudinally slotted tongue; a cap screw with its shank passing through the slot of the tongue and engaging bar whereby said dog can be adjustedboth vertically and angularly and set screws engaged in the bar and adapted sides of the tongue beyond the cap screw to hold the dog against displacement in angularly adjusted positions.

7. Feed mechanism for sewing machines comprising a feed bar with a vertical opening adjacent its forward end; a'feed dog bridging said opening; means whereby the feed dog is secured at its outer end with capacity for vertical adjustment relative to the bar; a screw stud adjustable in the top of the feed bar for supporting the inner end of said feed dog; and means for imparting to and fro and up and down movements to the feed bar.

. 8. In a sewing machine having a tubular worksupporting arm, a vertically reciprocating needle operated from above and a looper oscillatable transversely of said arm; feed mechanism including a feed bar longifeed bar.

tudinally of the interior of said arm with an end portion overreaching the looper and having a clearance opening in its top for the needle and the looper, a feed dog bridging'the opening in the feedbar; and means for impartingflongitudinal to and fro and up and down movements to the 9. In a sewing machine having a tubular worksupporting arm, operated from above the outer end of the arm, and a looper oscillatable transversely of said was? longitudinally of the end for imparting to.

to bear against opposite the outer end of said arm;

a vertically reciprocating needle armti feeding mechanism including a feed bar I.

M. interior of said'arm with a yoke-like portion at'its forward'end having an opening at the top and an openingat one side for 7 clearance of the looper, a feed dog bridging the banand means for im-" top opening of the feed parting longitudinal to and 'fro and up and down movement to'the feed bar.

10. In a sewing machine with a vertically-reciprocating needle and a cooperating looper; feeding mechanism including a feed bar; a

guard on said bar for steadying the needleincident to coactionpwith the looper in stitch-forfeeding mechanism including a feed bar, a guard on said bar at a level below that of the looper for steadying the needle incident to cooperation of mation, and means forimparting to and fro and the latter with the looper in stitch-formation,

means whereby the guard can be adjusted vertically and horizontally, and means for imparting to and fro and up and down movements to the feed bar.

13. In a sewing machine with a vertically-reciprocating needle and a cooperating looper; feeding mechanism including a feed bar, with a vertical opening adjacent its forward end for passage of the needle and a projection pendant from said forward end, a bracket piece secured to the inner side of the pendant projection on the feed bar with capacity for vertical adjustment, a guard secured to the bracket piece with capacity for horizontal adjustment, for steadying the needle incident to coaction with the looper in stitch-formation, and means for imparting to and fro movements to the feed bar.

14. Feeding mechanism for sewing machines comprising a feedbar; means for imparting to and fro and up and down movements to the bar; a feed dog on the feed bar pivotally connected at one end to the bar with capacity for angular adjustment laterally of the direction of feeding; and means projecting up from the feed bar to form a rest for the other endof the dog.

15. Feeding mechanism for sewing machines comprising a feed bar; -means for imparting to and fro and up and down movements to the bar; a feed dog pivotally connected to the end of the feed bar with capacity for angular adjustment laterally of the direction of feeding and reaching rearwardly over the bar; and means proj'ecting up from the bar for supporting the rear end of the dog.

16. Feeding mechanism for sewing machines comprising a feed bar; means for imparting to and fro and up and down movements to the bar; a feed dog extending rearwardiy over the top of the bar and having a vertically-slotted pendant shank; a securing screw passing through the slot and engaging intothe end of the bar, whereby the dog may be adjusted vertically and also angularly crosswise-of the direction of feeding about thescrew as an axis; and means vertically adiustable on the bar for supporting the rear end of the feed. dog.

forming element cooperating with the needle; feeding mechanismincluding a horizontal feed "bar with a-ver'tical opening through which: the

complemental stitch-forming element projects securing means whereby it may be adjusted on the feed bar transversely of the direction of feeding and fixed in such adjustment.

and a feed dog bridging the opening in the feed bar oversaid complemental stitch-forming element. 1 i

18. Feeding mechanism for sewing machines includinga feed bar and a feed dog carried thereby; means i'or imparting to and fro and up and down movements to the feedbar; means whereby the reed dog is secured to the bar with capacity for vertical adjustment; and separate means for engaging the 'feed dog at a right angle to the 19. Feeding mechanism for sewing machines including a-feed bar and afeed dog carried thereby; means for imparting to and fro and up and down movements to the feed bar; separate means whereby the feed dog is pivotally secured to the feed bar withcapacity for up and down and angular adjustment transversely of the direction of feeding; and separate regulatable means for engagingthe feed dog at, a right angle to the securing means to fix said dog in its transversely adjusted positions.

. .FRANK A. KUCERA. 

